Glass panelled sliding doors that open onto patios and gardens have become highly standardized, particularly those having aluminum frames. Each of the panels has a lengthwise bottom slot with imbedded rollers that ride upon one of two parallel tracks which fit into the slots. A prefabricated frame is installed in an opening in the building wall and this frame provides vertical recesses into which the ends of the panels are inserted when the doors are closed, providing air seals and making it difficult to insert a jimmy to pry a panel open. The standard door asseblies also provide catches that lock the closed panels to the frame, but these catches are somewhat fragile and can be readily circumvented by prying a panel upward off its track and pushing it inward.
Mantini U.S. Pat. No. 4,530,531 was cited by the Office in the parent to this case but Mantini's structure is far removed from the structure of the present invention and constitutes a relatively unsightly and much more inconvenient door locking means. Save for having the purpose of locking a sliding door Mantini is in no way suggestive of the invention to be described.
Innes U.S. Pat. No. 1,659,822 has also been cited. Innes employs the two plates of a door hinge to lock a hanging window sash to its sill. In particular, Innes plate hinges would not be useful where the sash fits into a recess formed by projecting strips, as shall be explained to be the case with sliding doors.